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BF 225 2007 225 hp -Alternator voltage output?

Brian silk

Brian silk

Regular Contributor
Happy New Year. Still waiting for my haulout to investigate my rough starts. Another issue I want to check out. My dash voltmeter started to read low so I turned on the voltage data field display on both my chartplotters. The voltage they both show is between 14.4 up to 14.9 v depending on revs. It seems way to high on the top end. The temp here is around 0 degrees C or 32F. I know the alternator is temperature regulated, but should it be this high? I have tested the two batteries with an electronic resistence tool and they both test right on spec for cold cranking amps. they hold a charge, and don't seem to be boiling of fluid.
 
Re: BF 225 2007-Alternator voltage output?

I forgot to mention, the dash voltmeter is not reading correctly, and all voltage measurements were checked at the batteries with a multimeter.
 
Re: BF 225 2007-Alternator voltage output?

14.6 +/- 0.3 volts is normal output directly from the alternator, so you are within specs. I have observed that when the batteries are cold, the output from the alternator is initially higher.

A strange quirk with the 225 and 200 is that the voltage coming off the ECM is about 0.8 to 1.0 volts lower - that is, the voltage reading on the Honda digital gauges will be between 13.6 and 13.9 volts. I asked my dealer about that a couple of years ago, and after looking into the issue he told me that the ECM just puts out the lower reading for some unknown reason. Go figure.

Anyway, just to safe-side it, I installed an analog voltmeter on my console wired directly to the power bus coming directly off the batteries into the cabin area.
 
Re: BF 225 2007-Alternator voltage output?

Thanks, that solves the mystery of the dash voltmeter which comes from the engine harness. It is always lower than the chartplotter voltmeter. I never had the plotter volt data header on so it was a surprise when I set it up that I was getting such voltage. I have the shop manual and for the life of me could not find an alternator spec. anywhere! The starting issue seems to have dissappeared all of a sudden, go figure! I have since filled the tank and added Techron to it to give the injectors a bit of a clean. I'll keep you posted. Thanks again!
 
yea, you need to short out the alternator with a paper clip, then put a load tester on the battery then use an amp clamp on battery cable to test the alt
 
read the service manual
you stick a paperclip in the alternator
i need to read up on it again
i just remember training on it
 
He is talking about "FULL FIELDING" the alternator to check for MAXIMUM AMP output. It is a "stress test" for the alternator. You would typically only do this if you suspected the charging system of not putting out sufficient charge current and identifying or eliminating the alternator as the problem. Not what you are experiencing in this case. If not done properly, you can damage the alternator so, by all means, read the procedure carefully if you decide to attempt the test.
 
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